Various power saving mechanisms may specify periods of time in which a wireless device may go into a sleep mode and power off its reception unit to save power. After each sleep period, the wireless device may restart or “wake up” the reception unit and reestablish wireless communication with a serving access node for a specific duration. During such a “listening interval,” the restarted reception unit of the wireless device may check for packet arrival from the serving access node and determine whether the wireless device should go back into the sleep mode or transition into an active mode.
If no data packets have arrived during the listening interval, the wireless device may go back to sleep to conserve power. However, if data packets are received at the wireless device, then the wireless device may transition to the active mode. There is a tradeoff between power savings during a sleep period and a potential delay in receiving data packets transmitted during the sleep periods. It may be desirable to have multiple sleep modes, in addition to active and idle modes at either end of the spectrum. In order to optimize power savings, a wireless device may enter deeper modes of sleep after reaching threshold times of inactivity. The listening intervals may be spaced apart by longer sleep periods at deeper sleep modes. This may help prevent more recently active wireless devices from experiencing longer delays than necessary before awaking to receive packets. Upon handover, an access node may force a wireless device into an active mode in order to establish status and transmit control signals.